IROS 2017 Papers

Medical ultrasound imaging robotics systems often comprise of complex control architectures and hardware integration to enable safe human robot interaction. In this paper, we investigate the applicability of a soft robotic end-effector for ultrasound intervention. A novel, parallel design is derived based on the medical requirements, which addresses common shortcomings in both robotic ultrasound systems and soft robotic devices. Individual actuators are developed and characterized and the performance of the overall platform is evaluated in regards to its stiffness and steerability. It is shown that the platform comprises relatively high longitudinal and transversal stiffness, while still being compliant enough to ensure the safety of the patient. The shear stiffness of the platform is 4.2 times greater than the shear stiffness of an individual actuator. The platform is capable of applying loadings of 10N along its longitudinal axis, which makes it suitable for the given application. Furthermore, the workspace of the platform is suitable to robot-guided ultrasound with a maximum platform rotation range of ±14.8°, while only moving ±7mm in space.

Surgeries involving interaction with soft tissue like the brain need to minimize shear and normal forces that can cause tissue damage or hemorrhage. Other surgeries require the ability to follow a complex, curved path, such as through an intestine or to a kidney stone. This paper presents a soft catheter that has the potential to aid in these challenging cases. The soft catheter is capable of apical extension in which the tip extends while the rest of the catheter remains stationary. This limits shear forces with the environment, easing movement of a body's tip through a constrained space. The soft catheter is pre-formed to patient-specific trajectories, meaning that normal forces against tissue would only arise due to errors between the actual and desired paths; we show decrease in normal force applied to the environment on the order of 100 compared to a standard catheter in a 30 degree bend. Setting the internal pressure allows for control of catheter stiffness, with a 500 times difference over the range of tested pressures. Manual operation to reach a surgical site requires only holding the correct orientation at the entry point into the body and setting the internal pressure of the catheter. This soft catheter could offer two benefits: the ability to apply low tissue interaction forces and reach challenging locations within the body.

This paper proposes a robust controller/observer for UAVs network anomaly estimation which is based on both Lyapunov Krasovkii functional and dynamic behavior of TCP (Transmission Control Protocol). Several research works on network anomaly estimation have been led using automatic control techniques and provide methods for designing both observer and command laws dedicated to time delay problem while estimating the anomaly or intrusion in the system. The observer design is based on a linearized fluid-flow model of the TCP behavior and must be associated to an AQM (Active Queue Management) to perform its diagnosis. The developed robust controller/observer in this paper has to be tuned by considering the time delay linear state-space representation of TCP model. As a first result, the designed controller/observer system has been successfully applied to some relevant practical problems such as topology network for aerial vehicles and the effectiveness is illustrated by using real traffic traces including Denial of Service attacks. Our first results show promising perspectives for Intrusion Detection System (IDS) in a fleet of UAVs.

Water pipe leakage is a common and significant problem around the world. In recent years, an increasing amount of effort has been put into developing effective leak detection solutions for water pipes. Among them, the pressure gradient based method developed at Massachusetts Institute of Technology excels for its sensitivity in low pressure, small diameter pipes. It can also work in both plastic and metallic pipes carrying gas or water. However, the method was only verified in static fluid pipes, and the previous sensor designs were unable to detect leaks when there is a significant water flow in the pipe. This is undesired as the inspection can only be performed when water service is shut down. A modeling analysis shows that fluid dynamic effects in the water pipe make the original sensors dynamics too slow to react to leaks. Moreover, this leak detection method is prone to false alarms such as obstacles in the pipes, but there is a lack of studies on this topic. In this paper, we present three things: the design of a new leak sensor that is fast enough to detect leaks in dynamic fluid environments, a prototype for 52mm-inner-diameter pipeline tested in an industrial facility, and a method to differentiate leaks from false alarms supported by the test results.

Collaborative robots, the so-called cobots, that work together with the human, are becoming more and more popular in the industrial world. An example of an application where these robots are useful is the assembly task. In this case, the human and the robot complement each other. On one side, the human can achieve more dexterous tasks, while on the other side, the robot can assist the assembly process to lower the physical and cognitive work load, e.g. to avoid errors, and in the same way reduce absenteeism. This paper describes a novel collaborative architecture for human-robot assembly tasks. The developed architecture is composed of four modules; face recognition, gesture recognition and human-like robot behavior modules are used to enhance the human-robot interaction, while the visual inspection module is utilized for quality control during the assembly process. A collaborative task consisting of the assembly of a box whereby the robot assists the human was designed and implemented on the Baxter robot. This was used as the application use case to validate the developed collaborative architecture.

We propose a flexible, reconfigurable robot which achieves rectilinear locomotion by coupling structural deformation and directional friction promoting a locomotion strategy ideal for traversing narrow channels. The robot uses two linear actuators to generate structural waves, which propagate through the robot lifting and changing the direction of motion of the contact points (feet) between the robot and ground. The reconfigurations of the robot allow different structural waveforms to alter the robot's gait. The paper describes the modular lattice structure used to build the robot; the finite element modeling approach used to understand the structural deformation induced by the linear actuators as well as the experimental validation of the prototype robot.

Minimally invasive surgery (MIS) has seen substantial development in recent decades. In MIS, particularly in laparoendoscopic single site (LESS) surgery, the surgical site is always crowded. One potential solution is the magnetic anchored and guidance system (MAGS), which liberates instruments from constraint of the accessing port. Current MAGS are all made by rigid components, which relies on articulated joints to maneuver inside the surgical cavity. Moreover, fabricating and assembling the MAGS are difficult due to the small size of the components. In this work, we present the design, modeling, fabrication and testing of a novel soft MAGS endoscope system. The system includes the external controller and the internal unit, which contains a soft body, two magnets and a replaceable wireless camera. It is compact, safe, lightweight and easy to make. Experimental results show that the system could offer stable maneuvering both in lab settings and in porcine model.

For actuating the magnetic microrobots, two types of magnetic actuation technologies have been used during the last past years. These magnetic technologies may be either electromagnetic coils or permanent magnets based systems. This second solution is not the most used by researchers, because of the difficulties to control the magnetic force. In this paper we propose a magnetic actuator prototype based on permanent magnets. In addition to the magnets, the actuator is also composed of a mechanical structure. This structure is used for positioning the permanent magnets, which allows to control the magnetic force generated by the actuator. We demonstrated in simulation and experimentally confirmed the ability of this actuator to generate both pushing and pulling forces.

Design and implementation of a fully-working multirotor Unmanned Aerial-Underwater Vehicle (UAUV) was successfully accomplished in the present work. The proposed prototype consists of a multirotor vehicle in an octo-quadcopter configuration, which is well suited for good transition between mediums. The mathematical model is provided by means of the Newton-Euler formalism, highlighting the impact of the drastic change in density on the vehicle dynamics. A hierarchical controller is employed for attitude tracking, utilizing a proportional control law in cascade with a body angular rate Proportional-Integral-Derivative (PID) controller. Altitude stabilization is achieved by a PID controller with compensation of the restoring forces, while a gain scheduling strategy handles the change of medium. Furthermore, the proposed platform was extensively tested in simulations and real-time experiments under real conditions, with promising results in both mediums, and seamless transition between them.

Silicone-based soft pneumatic actuator (SPA) is one of the key interests in soft robotic research. Currently, most of the SPAs bear a similar one-dimensional rod-like shape, regardless of their design and fabrication. There are few prototypes of SPAs with two-dimensional initial shapes, however, they are basically the linear combination of several one-dimensional SPAs. This paper presents a new class of silicone-based SPA named soft robotic pad (SRP). The SRP is shaped into a soft pad with a single flat air chamber and can generate different kinds of motions according to the internal constraint matrix within the SRP. In this paper, the design and fabrication of our SRPs are elaborated in detail, followed by the preliminary characterization of the different SRP prototypes. Although the current design is not optimized, our SRP prototypes prove the feasibility of the design and fabrication of a 2D shape-morphing SPA. With subsequent optimization, the SRP can work robustly in various real-world applications as strong flat artificial muscles for human joint rehabilitation, or as fins in marine robots.

This paper introduces a novel method for actuator design that exploits electromagnetic motors' torque and speed potential in jumping applications. We proposed a nonlinear optimization process that integrates (a) the control design to obtain the optimal ground reaction force, and (b) the mechanical design to narrow down the choices of motor/gearbox pair. Based on this method, actuators were designed and assembled into a leg prototype with two actuated degrees of freedom. Experiments demonstrated that the leg could achieve a maximum vertical jumping height of 0.62 m (2.4 times of leg length) and maximum forward jumping distance of 0.72 m (2.7 times of leg length).

Observations of fumaroles are important in forecasting volcanic eruptions. However, such observations are dangerous for humans because of volcanic gases and high-temperature steam that surround fumaroles. In previous study, a teleoperated mobile robot was developed to realize remote observations. However, it was observed that typical mobile robots were unable to reach fumaroles on a steep cliff. Therefore, extant research focused on the development of tethered small mobile robots to tackle thsese types of challenging cliffs to observe fumaroles. This study proposes a design of a tethered mobile robot to traverse a steep slope based on the analysis of slip and turnover. A few indoor experimental studies and field experiment were performed to verify the proposed design.

Soft robots, primarily made out of intrinsically soft materials, have flourished greatly in the past decade due to their advantages such as flexibility and adaptability over rigid-bodied robots. A rich repertoire of soft robots designed from intuitive or biomimetic approaches have been developed to provide new solutions for robots. However, these design approaches are limited by the designers' experience and inspiration, and a systematic design methodology for soft robots is still missing. We tackle this issue by mathematically recasting the design problem under the framework of topology optimization problem. To demonstrate the effectiveness of the proposed methodology, in this paper, we develop a pneumatically actuated soft gripper consisting of three fingers, each finger is able to undergo a free travel bending and deliver a grasping force. Hence, each gripper finger is designed as a continuum compliant mechanism to achieve its maximal bending deformation. The proposed soft gripper with complex shape is directly fabricated through 3D printing technology. Experimental results show that the deflected soft finger is able to achieve a 41° free travel bending and generate 0.68N blocked force upon 0.11MPa actuation pressure. This work represents an important step towards the goal of designing soft robots automatically.

Higher efficiency and the safety of hull inspection can be achieved by replacing the conventional methods with modern crawling robots. This paper consists of detailed study of the design and development of a crawling robot with a novel permanent magnetic wheel based on Halbach magnetic array. The magnetic array and the wheel assembly were designed based on the magnetic simulation results. Maintaining the adequate adhesion force as well as the friction force of the wheels were considered in designing the wheels. The crawling robot is equipped with a steering system based on Ackermann steering method hence the steering angles are controlled by an algorithm and actuated using servo motors. The driving system of the robot is equipped with four geared stepper motors and they are controlled separately by the algorithm according to the inputs of the controller. The control architecture and the components used for the robot control system are explained. The operator can remotely control the robot and inspect the hull surface via the camera feed available in the HMI (Human Machine Interface) of the robot. The prototype of the crawling robot was tested in a similar environment and the test results are included in the paper.

Targeting of small lesions with high precision is essential in an early phase of breast cancer for diagnosis and accurate follow up, and subsequently determines prognosis. Current techniques to diagnose breast cancer are suboptimal, and there is a need for a small, MRI-compatible robotic system able to target lesions with high precision and direct feedback of MRI. Therefore, the design and working mechanism of the new Stormram 4, an MRI-compatible needle manipulator with four degrees of freedom, will be presented to take biopsies of small lesions in the MRI scanner. Its dimensions (excluding racks and needle) are 72×51×40 mm, and the system is driven by two linear and two curved pneumatic stepper motors. The T-26 linear motor measures 26×21×16 mm, has a nominal step size of 0.25 mm and the measured maximum force is 63N at 0.65 MPa. The workspace has a total volume of 2.2 L. Accuracy measurements have shown that the mean positioning error is 0.7 mm, with a reproducibility of 0.1 mm. Velocity measurements with 5 m long tubes show a maximum stepping frequency of 8 Hz (maximum force) to 30 Hz (unloaded). These results show that the robot might be able to target lesions with sub-millimeter accuracy within reasonable time for the MRI-guided breast biopsy procedure.

High performance legged and mobile manipulating robotic platforms require light weight actuators with high torque density, efficiency, and accuracy. This paper introduces a new type of high reduction bearingless gearbox which is based on a gearbox with double-row planetary pinion, and can achieve high reduction ratios in a single composite stage. We discuss the practical issues which limit the applicability of the existing double row gearbox, and motivate our innovations. Several advantages of the bearingless gearbox over current approaches in terms of robustness, possible load distribution, manufacturability, and assembly are described. In the concept, all gear components float unconstrained, which is achieved by introducing an additional kinematic constraint that allows planets to be the same, in which case the planet carrier can be substituted with a secondary sun gear. The resulting planetary gearbox can be readily integrated into compact robotic joints. Its few lightweight components can be manufactured with high accuracy with standard machining techniques.

This paper is concerned with the analysis, design, and prototyping of rotary planar springs for robotics applications such as rotary series elastic actuators, or mechanical couplings. The key contribution is the development of a mathematical model, based on curved beam theory, that allows rapid design, analysis, and optimization of rotary springs that have arbitrary arm shape. The paper also introduces methods to reduce the spring mass via composite arm structures, or arm cutouts. A prototype is designed, analyzed and tested to demonstrate the validity of the model.

This paper presents an origami-inspired cable-driven continuum manipulator module that offers low-cost, low-volume deployment, light weight, and inherently safe human interaction and collaboration. Each module has a mass of around 110 g and integrates the actuation, sensing, and control sub-systems necessary for operation. The origami structure has 7.311 Nm/rad (0.128 Nm/degree) torsional stiffness while being capable of bending in two directions and changing arclength down to a fully collapsed state. A maximum contraction of 35 mm and bending angle of 35.5 degrees were achieved with 45 mm arc length. The module is capable of passively supporting a 1-kg mass at its tip, or 4 additional serially connected modules, bending approximately 6 degrees in the worst case. We also show that we can actively compensate for external moments by pre-compressing or pre-bending the module. We utilize an inverse kinematic control scheme and use it for both open and closed loop control following a circular trajectory. Our results indicate that the module motion follows the desired trajectory with an RMS error of 0.681 mm in the horizontal (x-y) plane and 0.373 mm in the z-axis with closed-loop control. We also assembled two origami modules in series and drove them independently, demonstrating the proof-of-concept of a modular origami continuum manipulator.

Minimally invasive neurosurgical robotic procedure performed under real-time MRI can be achieved with a robot that is head-mounted and fits in a standard MRI bore. The design of a remotely-actuated cable-driven robotic system is presented in this work. A head mounted insertion module has been developed to advance the robot module towards the target brain tumor. The robot module is formed by snapping together a reusable part that leads to the remotely-placed actuators and a disposable part which includes the previously developed spring-based MINIR-II robot. Gear transmission mechanism was implemented in the robot module to transmit the force from the actuators to the end effectors of the robot. The robot module and the insertion module are lightweight and compact with a total weight of 250 g and a total height of 222 mm. This allows the entire setup to be placed vertically on a patient's head in a closed MRI bore. The compact design of the robot module has been achieved, significantly due to the innovative modifications made to the structure of standard spur gears and smart routing of the cables around the gears. The completely MRI-compatible Bowden cable module has been implemented to allow transmission of significant force of around 10 N required for the actuation of the robot. A static friction model has been used to estimate the friction coefficient for the Bowden cable module as a preliminary step towards the complete modeling of the entire robotic system. The relationships between the input displacement and force of the cable at the actuator end and those at the middle and end robot segments were determined through experiments and discussed. A functional robotic system has been presented with the robot being inserted into the phantom tissue and only the end segment actuated back and forth.